Mercury Water pump problems

[JW]

Oops, I was wrong on the compression. Now for punishment, I have to list Per my Mercury service manual:

All models, using a fully charged battery, throttle shutters wide open and cylinder block warm: 105/140 Jet/135/150/XR6/MagIII/175/200/XRI/Promax 110-135 psi. Variance between cylinders should not exceed 15 psi. So you're good to go!

I agree with everyone else, your impellor looks TERRIBLE. Try changing that out first before you change the whole pump assembly. One thing you can try to check for blockage: Pull the T-stat and run a pressure hose up your midsection into the water tube and see if you get flow out of the block. Or, push water backwards down the block and out the water tube. I had to do that with a motor last summer that was all clogged to heck.

 

[Chris]

you can not put the pump together wrong unless you leave out the key

direction on instalation makes no difference
oil change pumps use the same type impeller and they run either direction to
drain or fill the motor

i would guess the dealer is at fault here
when you replaced the t-stats did you find any black chunks?

get a new w\p kit with a new housing


daren

Maybe I'm wrong, dunno.

But I thought on some waterpumps you have to set the impeller blades so they're winding in a certain direction. As smallblock said, you usually set them when you put the waterpump cover on. You do so by turning the drive shaft. They then all bend in one direction but it has to be the correct direction.

I'm usually working with old small junk, so I could be wrong.

I know on one of my old gals the impeller got set wrong by a previous owner and it wouldn't pump water. And when I took the impeller which was reported to be new, the excess friction of the impeller turning the wrong way had done a pretty good number on it.

 

[Mark]

Hey guys is it possible that the water pump is bad or maybe the lower part in the gearcase? If the shaft is turning the impellor while it's idling then I've got blockage in the foot, right? Another words i'm not drawing water from the LU. If i'm wrong on this please correct me.

Right!

 

[Mark]

Maybe I'm wrong, dunno.

But I thought on some waterpumps you have to set the impeller blades so they're winding in a certain direction. As smallblock said, you usually set them when you put the waterpump cover on. You do so by turning the drive shaft. They then all bend in one direction but it has to be the correct direction.

I'm usually working with old small junk, so I could be wrong.

I know on one of my old gals the impeller got set wrong by a previous owner and it wouldn't pump water. And when I took the impeller which was reported to be new, the excess friction of the impeller turning the wrong way had done a pretty good number on it.

Right!

 

[smallblockford]

you can not put the pump together wrong unless you leave out the key

direction on instalation makes no difference
oil change pumps use the same type impeller and they run either direction to
drain or fill the motor

i would guess the dealer is at fault here
when you replaced the t-stats did you find any black chunks?

get a new w\p kit with a new housing


daren

you can put one in backwards it isnt pumpin oil that would keep it lubed all the time it is pumping water and when in a lake it is submerged. when not it isnt prob was dry but you set the blades back wards leave em set and you will see the blades come off i have seen it better of not puting them in wrong rotation specially when the manual says replace anually that meens yearly but they only do that to cover there as_ .

 

[Rob B]

Now that my frustration has subsided, I'm eliminating each part of the motor. So with the LU out I took out the t-stat flushed out each side one at the time with the water nozzle. There's nothing in the cooling system, I had plenty of water flow coming out of the cooper tube. Today I ordered a new water pump kit w/ base plate from the Mercury dealer. Tomorrow I'll finish taking the water pump apart and hope that's it's isolated in the LU.

 

[Chris]

cm,

The thread that I posted the link to earlier has a decent set of instructions on how to do the waterpump.

Given how the impeller wore prematurely, something was amiss - I think. I would guess that either the impeller had the fins set in the wrong direction when the cover was put on, or there is a blockage below the water pump which caused it to be running dry. Whatever is or isn't going on with the top end of the motor, I would think has little to do with the impeller wearing prematurely like it did. So once the waterpump is fixed up, you can then deal with the other issues next - if there are any.

So my advice is check for a blockage from the water inlets to the pump. Look for old impeller bits, sand, debris etc. Make sure that's all flushed out. Then reinstall the new waterpump kit and make sure the impeller blades are set in the right direction when the cover goes on. That's usually done by turning the driveshaft clockwise as you install the waterpump cover over the impeller- but double check the direction the drive shaft has to be turned to be sure.

 

[Rob B]

cm,

The thread that I posted the link to earlier has a decent set of instructions on how to do the waterpump.

Given how the impeller wore prematurely, something was amiss - I think. I would guess that either the impeller had the fins set in the wrong direction when the cover was put on, or there is a blockage below the water pump which caused it to be running dry. Whatever is or isn't going on with the top end of the motor, I would think has little to do with the impeller wearing prematurely like it did. So once the waterpump is fixed up, you can then deal with the other issues next - if there are any.

So my advice is check for a blockage from the water inlets to the pump. Look for old impeller bits, sand, debris etc. Make sure that's all flushed out. Then reinstall the new waterpump kit and make sure the impeller blades are set in the right direction when the cover goes on. That's usually done by turning the driveshaft clockwise as you install the waterpump cover over the impeller- but double check the direction the drive shaft has to be turned to be sure.

Chris thanks for the tip and the link. I did check the impellor to see if i had put in correctly, which was clockwise rotation. I agree, I think the blockage is somewhere between the water inlets and the pump base. I'll know more when i get the complete water kit and and finish taking the water pump apart.

Hopefully someone can learn from my frustration and oh Mercury OB's aren't that bad.

 

[kct11]

from the pictures, it was turning the correct way.

 

[groucho]

And 170.......if you remember from my post waaay back when you were first asking about replacing a water pump on this motor. Be sure to lube the impeller up when you install it in the housing so you don't prematurely wear it out and cause it to run dry and burn up before water gets to it.

Sometimes it's the little things that will give you fits.....I don't know if that's the cause here but making sure it's installed in the right direction and not putting in dry will make that impeller live a long time.

I hope you're back out on the water w/ a strong tell-tale soon!!

 

[Rob B]

And 170.......if you remember from my post waaay back when you were first asking about replacing a water pump on this motor. Be sure to lube the impeller up when you install it in the housing so you don't prematurely wear it out and cause it to run dry and burn up before water gets to it.

Sometimes it's the little things that will give you fits.....I don't know if that's the cause here but making sure it's installed in the right direction and not putting in dry will make that impeller live a long time.

I hope you're back out on the water w/ a strong tell-tale soon!!

Groucho I did remember what you said about lubing up the impeller before installing it. Thanks for the tip!!!

 

[BullittBen]

You know, I've been meaning to ask you, who was the previous owner of that boat? Any idea? I knew a guy in North Charleston a few years ago that had what I think was a Checkmate similar to that. His name was Kenny. He moved out toward Pinopolis or something. I knew him fairly well, but I wasn't into boats at the time, so I don't know exactly what his boat was. I know I used to hear it in the driveway getting revved entirely too much on the muffs though. If it was his boat, I may be able to get the full history on it for you.

 

[Rob B]

You know, I've been meaning to ask you, who was the previous owner of that boat? Any idea? I knew a guy in North Charleston a few years ago that had what I think was a Checkmate similar to that. His name was Kenny. He moved out toward Pinopolis or something. I knew him fairly well, but I wasn't into boats at the time, so I don't know exactly what his boat was. I know I used to hear it in the driveway getting revved entirely too much on the muffs though. If it was his boat, I may be able to get the full history on it for you.

Ben i bought this from Marshals Marine out of Lake City SC. The only thing I know is the guy was a local to that area and he had two sons in their 20's. The sons use the boat for sking.

 

[Rob B]

Update on LU

Well Guys I've found the problem w/ the help of a friend who works at a Mercury Dealership. As you remember I had ask for some info on replacing the
WP/impeller a while back. I got good info so I decided to do this myself. Most of probably remember what the upper housing look like and how hard it was to remove the impeller, thank's boston predicter for that tip.

Now to the problem: The base plate. Yep the damn base plate was so warp that when i replaced the WP& impeller the upper housing didn't seal properly.The LU was sucking air, no water dry impeller. All this because the previous owner ran the damn motor so hot it melted the wp and base together. I should've replaced the whole upper and lower parts at one time.

So when I get the LU back w/ the used parts i'll post pics and a nice steady stream of water coming out of the telltale outlet. A big thanks goes to all that help/had suggestions, as they say on the PGA Tour "These/you guys are good" Oh and did I mention Mercury Motors aren't that bad

 

[supergenius74]

glad you got it worked out, i was always told to replace the entire pump assembly and not just the impeller and I always have and so far I have never had impeller propblems. I would also suggest a water pressure gage, they should be standard on outboards in my opinion, 35 bucks and you will always know if you have good water presssure.

 

[Chris]

Ditto on what 74 said.

I just buy a complete kit and replace it all.

I'm glad you got it sorted.

Now you can fire it up and see if the hard starting problem still exists.

 

[Rob B]

glad you got it worked out, i was always told to replace the entire pump assembly and not just the impeller and I always have and so far I have never had impeller propblems. I would also suggest a water pressure gage, they should be standard on outboards in my opinion, 35 bucks and you will always know if you have good water presssure.

74 I do have a water pressure and temp gauge that i installed. I installed both because of the problems i was having with the water pump. Do a search it's somewhere on here. I learned the hard way thankfully i didn't burn up the engine.

 

[Rob B]

Ditto on what 74 said.

I just buy a complete kit and replace it all.

I'm glad you got it sorted.

Now you can fire it up and see if the hard starting problem still exists.

Chris my friend at the merc dealership said that a weak battery causes the motor not to fire/crank. My understanding is that you have to have at least a 900 amp battery to crank the engine. He said that this engine is similar the FICHT evinrudes which requires alot of juice to fire/crank the engine.

 

[Chris]

Chris my friend at the merc dealership said that a weak battery causes the motor not to fire/crank. My understanding is that you have to have at least a 900 amp battery to crank the engine. He said that this engine is similar the FICHT evinrudes which requires alot of juice to fire/crank the engine.

A lot of the various electronic components on Mercs are integral to each other. Last year I had a bad switch box, and it kept setting off the beeper. My beeper also goes off when my battery is low and I try to start mine up.

I'm hoping you might fire yours up and all is good.

 

[Rob B]

The base Plate

Here is the base plate that was removed from the LU. As you can see it was melted and warp. The good news I've water coming out of the telltale outlet!! Also the motor fires w/ no trouble, the cause a bad battery.